On Tuesday 22 May 2018 00:51:08 Erik Christiansen wrote: > On 21.05.18 22:19, Gene Heskett wrote: > > Greetings all; > > > > The first "tap hat" is done, and has a 5mmx.8 tap mounted in it. > > When the box of 10 different grubscrews arrived, it seemed like a good > idea to write the size and _pitch_ over each compartment, on the > transparent lid. That saves time later. > > > But I've got to profile how far off center that 3" chuck mounted to > > my rotary table wobbles, so I can write a short thing to drill the 4 > > holes in the side that hold the grub screws, I must have been an > > hour and a half piddling with that and actually get the grub screws > > centered on the tap butt flats. > > For the original tap hats, all I used to center on the cylindrical top > was the old 6" steel rule seesaw, with a pointy tip in the drill > chuck. When the seesaw's level, it's centered. (Certainly well enough > to hold the bum end of a tap already aligned in a close-fitting bore, > I figure.)
I don't think I've got one of those seesaws, but I do have a dial so I can watch the movement as it turns, record the offsets and use them in the code. That would have to be done in a single touchoff as that table has no home switch. And it might be a good idea to sweep the top with an 1/8" flat nosed mill to make a small flat to drill into. 3 tool changes. The drilling is throwing up a ridge around the hole just tall enough to interfere with inserting it smoothly into the R8. > > > Only about 50 more to go. :( > > ISTR that you've made them all out of a bar of ¾" brass, so the one > centering ought to do for the lot? With an A axis to spin the 90°, you > can drill 4, then tap 4, for ¼ of the tool changes. Yes, moving the y a few thou to compensate for the chucks wobble. > > Erik > 7/8" brass rod. More room for longer, or doubled, grub screws. But IIRC, I'm going to have to make a tube to hold them far enough away from the jaws else the spindle will hit them. Or maybe chuck the rear end of one of the modified 7/8" R8 collets, put the brass in the R8 backwards, using the side screw as a depth stop, and put the tables tailstock against the central hole. That will leave the body of the rod projecting and far enough from the chuck jaws that everything clears. It would improve the grip if I had an R8 socket and a drawbar to close the R8, but with the tailstock supporting the end, it ought to work. First thing I'll try today when I get to the garage. Thanks Erik. Writing about this makes me think of better ways to do it. -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
